01 Nov, 2011
1 commit
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The dm-bufio interface allows you to do cached I/O on devices,
holding recently-read blocks in memory and performing delayed writes.We don't use buffer cache or page cache already present in the kernel, because:
* we need to handle block sizes larger than a page
* we can't allocate memory to perform reads or we'd have deadlocksCurrently, when a cache is required, we limit its size to a fraction of
available memory. Usage can be viewed and changed in
/sys/module/dm_bufio/parameters/ .The first user is thin provisioning, but more dm users are planned.
Signed-off-by: Mikulas Patocka
Signed-off-by: Alasdair G Kergon
